Photoshop CC 2015: Convert to halftone bitmap wacks the image into unusable tiles

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Using Image mode bitmap and convert to halftone breaks the image into unusable random size and shaped tiles. This is a new problem with CC 2015
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restlest

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Posted 3 years ago

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restlest

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This seems to be fixed but a new problem is now happening when a try a Color Overlay in Layer Style with the color I choose displaying large diagonal stripes as the color overlay. The fix for the bitmap to halftone doesn't change this problem.

As to the bitmap halftone fix, it seems to vanish after I changed the Performance setting by unselecting from Advanced Graphics Processor setting all checkbox options, and then turning them back on one by one and restarting each time.

None of these, or even turning off Advanced Graphics performance fixes the diagonal stripes. For what it's worth, running Yosemite 10.10.4 I'm getting the same issue with CS 6.0
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Chris Cox

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So far I can't reproduce a problem with bitmap mode. So we'll need more details to reproduce it.
What exactly were you doing?
Were you converting grayscale to bitmap mode? If so, exactly what settings did you select?

Nor can I reproduce any problems with color overlay -- so, again, we need more details to reproduce the problem.

Changing the GPU settings means that it could have been just another MacOS 10.10 video driver bug. Apple is aware of the bugs in the MacOS 10.10 video card drivers and still working to solve them.
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Karl LaRocca

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This often happened to me with Photoshop CS6 and now with CC as well. Generally with larger >40MB files working at 720dpi I think it might be a bug in the split channels code. I just split channels on a large ( 17Kx13K pixels ) CMYK and saved each one as a grayscale tiff and photoshop saved a glitched file each time, so it is not part of the bitmap routine. If I copy and paste each channel into a new grayscale I have no problems.
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Jeffrey Tranberry, Sr. Product Manager, Digital Imaging

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Hi Karl,

Does this happen every time (100% reproducible) with this particular file?
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restlest

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The bitmap problem has disappeared after taking the steps mentioned earlier.
The Cover overlay is being done to preview CMYK screen separations. This worked prior to the upgrade, as early as the week before the upgrade, and then stopped working. Above is an example and was done the following way.

Converting a gray CMYK channel back from bitmap halftone to gray scale with a 1:1 size. Zoom into the image and with the Magic Eraser tool set to Contiguous and Anti-alias unchecked and Tolerance at about 10 click on white area in the image and then delete the selected cells. Copy the entire image into a new RGB document or black channel. As this target image is RGB use the Color Overlay by clicking on the layer thumbnail and choosing a process CMYK color in Color Overlay to fill. By merging the effect down to a new empty layer and using Multiply 100% I would get a good approximation on how the 3 color layers will look when screen printed.

Instead, I get something like the example above for each color. This used to work fine, and on all the images I worked with until this week.

I've been looking for another way to affect this previewing effect with no luck.
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Chris Cox

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Have you tried disabling GPU drawing entirely in Photoshop, and restarting the application?
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restlest

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Yes, I have, with no change. Thanks for helping me.
In fact, other issues have been popping up.

This combination of the Apple upgrade and Photoshop CC2015 is just very unstable.
I get strange dotted grid lines if I've selected the whole image and do some work, although if I resize the image and perhaps deselect a selection, it corrects itself. When the grid lines (dividing the image in two equal parts left and right horizontally and approx. 80/20 vertically) show in one open image, the lines show in others.

But the biggest issue is photoshop will sometimes just freeze, inexplicably. Forcing me to hard boot. I have plenty of memory with 64GB.
I hope this gets passed on to Apple and the two companies work this out.
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Chris Cox

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OK, that's weird. So it isn't a GPU drawing issue, but you are seeing some other corruption or drawing problem that I can't seem to reproduce.

Yeah, selections have problems with the GPU off - that's being worked on.

Does the whole machine freeze? If so, you're looking at an OS bug, a low level driver bug, or defective hardware.
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Krista Sharp

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I am having the issue mentioned in the original post. Every time I convert to the halftone bitmap I end up with my image broken up into tiles. This include blocks of complete black as well as different crops of the image.
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Chris Cox

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I cannot reproduce this -- so we need more details about your system so we can try to reproduce what you are seeing.

Also, try disabling GPU drawing as explained above.
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travis bothner

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I'm getting the sam issues..... Adobe CC 2015 - 2013 MacBook Pro 15" Retina
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Chris Cox

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Please see the previous replies -- we cannot reproduce this, and need more information to figure out what you are seeing.
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restlest

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I have completely disabled GPU drawing entirely and still get the blocks. Just to be clear, this was disabled under Preferences in the Performance Tab. I unchecked the Graphic Processor. I'm running PS CC2015.01, the most current version.

There is nothing unusual about my system but I would be glad to provide any information you want. My partners computer does the same thing so I suspect this bug is quite common. And now there is another posting.

Since this has been an issue with me (I'm the original poster) for at least one CC upgrade I'm considering canceling my subscription because it's not giving me any advantage to maintain.

I have noticed that changing the size will sometimes correct the blocking or lines, but not through all size changes within navigator.
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restlest

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One might think since resizing in navigator does accurately display the separated CMYK layers (after running Split Channels) instead of the blocks and/or lines or noise that saving each layer of the CMYK will allow one to re-open and see the image. Not so. In fact, opening a saved layer displays only a black square.

If I wasn't clear in the post today I was simply converting an image to CMYK from RGB, one that was 8inches by 8inches square. And then from the Channel menu I chose Split Channels. It was these derived channels that showed blocks, grids, or dots. And saving only showed black images.

I was also using default color spaces. US Swop coated V2 from ProPhoto RGB.
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restlest

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Perhaps a temporary solution. Rather than working with the image and its layers, whatever they may be. If I first flatten the image and then convert to CMYK and then split channels, the process works as expected, the layer to images are fine.

I would intuit that this is not a driver-related issue but a bug in the split channel rendering. But whatever it is, perhaps this might help located the source of the problem.
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Chris Cox

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We haven't heard about this from anyone else, and we cannot reproduce the problem. So yes, we're going to need a lot more details about exactly what you are doing, and what might be causing problems (third party plugins, extension panels, maybe even what palettes you have visible).
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restlest

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I'm not using any extensions or plugins. Nothing that doesn't come with Photoshop as default.
The view is the Photography Workspace, with Navigator, Adjustments and Layers on the right and a vertical Toolbar on the left and in this case the Selection Tool defaults on the Top which has no presets defined.
The Application Frame, Options and Tools are checked along with Adjustments Layers and Navigator.
It's a Single Modal Window, self-contained.

I'm using OSX Yosemite, Version 10.10.5 on a Mac Pro (Lat 2013)
It's a 3.7GHz Quad-Core Intel Xeon E5
64GB 1866 MHz DDR3 ECC
AMD FirePro D300 2048 MB

The problem is intermittent so it's been hard to determine what might be causing it. I usually have LightRoom CC2015 opened, and may or may not have other images. Sometimes I wonder if all the memory I have is causing problems, though my partner has less memory on her computer but has seen the same problem.
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Chris Cox

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Could you write down what you're doing step by step, so we can try again to reproduce it here? By writing it down, and trying it a few times yourself as you read the list, you might remember some detail that might have been left out before. This sort of bug really needs exact steps, with every single step accounted for to reproduce the error. Once we can reproduce it, then we can find the cause and fix it. But without steps that reproduce it, all we can do is guess.

If you don't want to post the list (or action) on the forum, you could mail it directly to me at ccox (at) adobe (dot) com.
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Angela Mead

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I also have this problem. I need smooth round dots not rough splotches.

I have a retina 5k iMac running the latest photoshop.
I open the greyscale photo, image,mood, bitmap, output 1200P/i & halftone
Frequency 24line/inch angle 0, round

if the dot is full it looks fine if not - rough splotches
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Chris Cox

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We still have not been able to reproduce the problem.
We need exact steps to reproduce it.
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restlest

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I can attach an image to show an issue with doing CMYK channel separations. After separating and simply saving each channel as a PSD file the image looks fine in Photoshop but when I view the saved file (later in PS or in Preview) this new image is entirely black. This is the case for each channel. They are all black.
Sometimes the initial channel view after separating will show a tiled image that is not at all representative of the original with the tiles being arbitrary. Saving these may also be simply a black image file, or representative of the wacky tiles I'm seeing on screen.

This is entirely the steps I've taken.
I even shut down the computer and restarted.
Nothing else had been opened after restarting.

After restarting, I immediately opened LightRoom and selected "Edit in .. (my photoshop)" and selected "Edit with a copy of LightRoom adjustments". I changed from 16 bit to 8 bit and then did the channel separation. Strangely even though there were no layers in the image, only the background, the channel separations created an extra "transparency" layer.

The next step was simply to save the channel. I've done tiff and PSD saves. Same issue.
On the occasion I'm describing, saved as a psd file, each channel is 907KB.
Earlier when I did this and got arbitrary tiles for the CMYK channels and saved immediately but as tiffs, they were each 56.4 MB.

For what it's worth this is the first time I selected "Edit with a copy of lightroom adjustments" so I don't think this step is the cause of the problem.

If I select all and copy one of the channels, and then create a new image and paste the copy into it, I get an all gray image with noise.

These steps can't be more simple. And the fact that others in these posts are getting similar results makes me think you're not really trying. Or the computers in your lab aren't really similar to what those of us with the problem are using.
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restlest

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And why aren't you asking for the images that we are having problems with?

Perhaps the issue is with the source image. In the case of this particular problem I have done Photoshop and Lightroom processing including changing the resolution and resampling and using the lightroom profile correction under lens corrections to make the image vertical.

And without using constrain crop my final image had a white background in the upper left hand corner. By white I mean no image, just background.

And then if I split channels with the white in the upper left, I would get a transparent channel as the 5th channel. If I rotated the image 180* so the upper left quadrant would be image not white, I would instead get a bunch of arbitray tiles rather than a representative C, or M or Y or K channel. Along with the 5th channel.

Just a thought. My original I'm working with is 775 MB so I don't want to attach it.
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restlest

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For instance, If I open the original non-split photoshop file in Gimp 2.8, a free image editing program, and separate the RGB into CYMK in Gimp and then export this file and then open it in Photoshop and split these CMYK channels (done with Gimp) and save them, each channel is correctly rendered as an image. Not black or not tiled.

This suggests to me that the issue is in the initial CMYK conversion done by Photoshop, not in the splitting done later in Photoshop.
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Chris Cox

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The source image isn't likely to be the problem - but we do need the exact steps needed to reproduce the problem, because so far we cannot reproduce it.
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restlest

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Okay. So you have the exact steps above and from a clean reboot, maybe that will help. Thanks.
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Shawn Moore

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Trying to do CMYK separations for screen printing and having the same issue. Using Photoshop CC 2015 on a Windows 7 64bit machine.
My steps as follows:

1. Open my art.ai as CMYK and 300ppi
2. Split channels. ( Also getting an extra transparent channel)
3. Starting with Key Plate, Image- Mode - Bitmap (Method Halftone Screen - frequency 85 - angle 112.5 degrees- Shape Round)

After that the image is scrambled and unusable. I've tried saving the channels separately as .psd and reopening them individually and the image is entirely black.

I did these same steps with a simple portrait off of google images and it turned out fine. I then saved my art.ai as .jpeg and as .tiff and had the same bad results with one result adding blocks of the previous separation (portrait image from google). I've completely uninstalled Photoshop and reinstalled with no success.

Please help. I am stuck at this point.

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Shawn Moore

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I was able to split the channels and bitmap after rasterizing my art in Illustrator and exporting as a .jpeg.
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Victoria Gritton

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I am having the same problem. El Capitan. 10.11.3. running the latest photoshop.

Steps:
1. Open Photo
2. Image > Mode> Bitmap
3. Output > 300
4. Frequency >24line/inch angle 0, round

Then my image gets split into multiple images, unusable. See screenshot.
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Chris Cox

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Still can't reproduce it (and I just tried those steps 15 times).

Most likely there is still some important step or piece of information being left out -- which we will need to reproduce the problem.
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Victoria Gritton

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Can you list all of your steps? Maybe something isn't matching up. Thanks.
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Chris Cox

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I used the steps given (which have to start with a grayscale image to work).
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restlest

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There is no important piece of information being left out. You've had a number of responses to this post. My earlier one stated all the steps, from booting up to the problem encountered. That simple. I have offered to send you an image. Perhaps that is the step that is different in all these cases. Doesn't that satisfy the reproducibility issue you keep bringing up.
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Victoria Gritton

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Nope, there is nothing else I am doing. Nothing else, not one more or less thing. Looks like I will have to ask elsewhere on this forum and consult a different expert because it makes no sense that you are not having the problem.
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Chris Cox

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We are spending quite a bit of time trying to reproduce this - but we cannot, even when testing on a wide variety of systems.

Again, there is some important piece of information being left out -- and that bit is necessary to reproduce the problem.
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Alexis Kraus

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I'm having the same issue as described by everyone else above. updated Photoshop CC yesterday. 
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Perry Heauxlstein

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Ive had the same problem! and it only started doing it this week. I've done a whole lot of CMYK bitmapping/ color separation stuff on Photoshop in the past with no trouble. has this been happening for everyone only recently?
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Chris Cox

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Some people have had problems for months, but we have not been able to reproduce the problem at Adobe.  There is some missing step/factor that we need to figure out.
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Chris Cox

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Does this problem go away if you flatten the image before splitting channels?
It sounds like it may be the same cause as https://feedback.photoshop.com/photoshop_family/topics/split-channels-on-large-cmyk-files-gives-glit...
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jitterbug

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yes I was having the same problem as described by others after upgrading ot 2015.1.2 on el capitan, artifacting image break up. Flattening the image prior to split channels seems to work for me.
(Edited)